CREDIT QUALITY ASSESSMENT (Credit Quality of Loan Portfolio) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	$ 13,417	$ 14,762
Non-accrual loans	26,336	29,211
Current loans	4,274,495	3,883,835
Total loans	4,314,248	3,927,808
Commercial
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	587	1,335
Non-accrual loans	6,703	5,833
Current loans	490,658	460,118
Total loans	497,948	467,286
Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	2,213	1,912
Non-accrual loans	2,967	2,859
Current loans	450,649	451,886
Total loans	455,829	456,657
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	896
Non-accrual loans	136	137
Current loans	292,307	307,246
Total loans	292,443	308,279
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	775	2,056
Non-accrual loans	5,575	8,107
Current loans	1,106,360	917,950
Total loans	1,112,710	928,113
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	414	2,223
Non-accrual loans	3,582	4,823
Current loans	853,200	768,506
Total loans	857,196	775,552
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	9,428	6,340
Non-accrual loans	7,196	7,257
Current loans	904,811	828,095
Total loans	921,435	841,692
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
Non-accrual loans	177	195
Current loans	176,510	150,034
Total loans	176,687	150,229
31-60 days
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	9,983	8,665
31-60 days | Commercial
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	587	663
31-60 days | Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	2,107	808
31-60 days | Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	896
31-60 days | Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	775	850
31-60 days | Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	414	1,479
31-60 days | Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	6,100	3,969
31-60 days | Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
61-90 days
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	3,209	5,865
61-90 days | Commercial
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	672
61-90 days | Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	106	1,104
61-90 days | Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
61-90 days | Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	1,206
61-90 days | Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	744
61-90 days | Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	3,103	2,139
61-90 days | Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	225	232
> 90 days | Commercial
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days | Consumer
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days | Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days | Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days | Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	0	0
> 90 days | Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	225	232
> 90 days | Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Recorded Investment Past Due [Line Items]
Total past due	$ 0	$ 0